CHICAGO (AP) The series opener between the Chicago Cubs and St. Louis Cardinals has been postponed because of poor weather.

With light snow falling and the temperature around 30 degrees, Monday night's game was postponed about six hours before the scheduled first pitch. It will be made up as part of a split doubleheader on July 21.

The Cubs are pushing their rotation back a second day with Tyler Chatwood - originally scheduled to pitch Sunday against Atlanta - starting Tuesday and Jon Lester going Wednesday. St. Louis' Adam Wainwright will have his start moved back a day to Tuesday. But the Cardinals will go with Luke Weaver instead of Michael Wacha on Wednesday.

The postponement was the third on the Cubs' first homestand of the season - and second in as many days. Sunday's series finale against Atlanta got pushed back to May 14 because of rain.

There were 21 postponements in the majors through Sunday.

The Cubs were hoping to get Anthony Rizzo (lower back tightness) back from the 10-day disabled list on Monday. But the postponement delayed the three-time All-Star's return.